The present invention relates to a quick exhaust valve which is used in various types of equipment utilizing compressed air. In particular, these include blood-circulation accelerators.
When the body is stressed or subjected to external pressure and then released from it repeatedly, the blood flow of the stressed part is accelerated, resulting in improved blood circulation. This result is a good treatment for diseases.
A blood-circulation accelerator which is capable of automatically and securely performing such stressing and releasing operations by utilizing compressed air is known. It is desired that such a blood-circulation accelerator perform the release of compressed air as quickly as possible. In order to achieve this objective, the present inventor has proposed a quick exhaust valve in Japanese Utility Model Laid-Open Publication SHO 61-42600.
In the quick exhaust valve, as shown in FIGS. 5A and 5B, an inlet port 2 for compressed air is provided at one end of a valve body 1, an opening 4 for connection with an air bag 3 is provided at another end thereof, and an exhaust port 5 is provided at a position opposite to the inlet port 2. A strip-shaped flexible valve membrane 6 with both ends fixed is also positioned in the valve body 1. As shown in FIG. 5A, a supply of compressed air from the inlet port 2 acts on the valve membrane 6, so that the valve membrane 6 closes the exhaust port 5. At the same time, the valve membrane is projected through the connection opening 4 into the air bag 3.
Thus, the compressed air is supplied into the air bag 3.
Unfortunately, the quick exhaust valve of the type comprising a strip-shaped valve membrane 6 has drawbacks. Because of the pressure acting on both sides of the valve membrane 6, the valve membrane 6 undergoes resistance in its motion during air exhaust. This results in poor operation at low pressure or small quantity of air.
Furthermore, since the connection opening 4 and the exhaust port 5 are perpendicular to each other, the air flow during exhaust is poor, resulting in inferior quick exhaust performance. Moreover, noise is generated due to a pulsating flow during the exhaust.